Field of the Invention
The present invention relates to a gas-filling apparatus and a method for filling gas.
Description of the Related Art
A conventional gas-filling apparatus for supplying gas to a pressure accumulator is disclosed in JP 5248607B (which will be hereinafter referred to as Reference 1). As illustrated in FIG. 10, the gas-filling apparatus disclosed in Reference 1 is provided with a gas flow circuit 63 in which a compressor 61, buffer containers 62, and on-off valves V61 are arranged. A gas supply source 65 is connected to the gas flow circuit 63; thereby, the gas can be supplied from the gas supply source 65. In addition, a tank mounting unit (such as a vehicle) 66 is connectable to the gas flow circuit 63 and the gas can be supplied through the gas flow circuit 63 to a tank of the tank mounting unit 66. In particular, in the case of supplying the gas to the tank of the tank mounting unit 66, at the same time as the gas stored in the buffer containers 62 is supplied to the tank (pressure equilibrium), the gas supplied from the gas supply source 65 is compressed by the compressor 61 to be supplied to the tank without passing through the buffer containers 62. Thus, in the gas-filling apparatus disclosed in Reference 1, the supply of the gas from the buffer containers 62 and the supply of the gas from the gas supply source 65 through the compressor 61 are conducted at the same time; thereby, a prompt gas filling can be realized.
In the gas-filling apparatus disclosed in Reference 1, the gas is supplied simultaneously from two systems; therefore, the prompt gas filling can be realized. However, in the simultaneous supply of the gas from the two systems, a volume of the gas compressed by the compressor 61 and a flow rate of the gas discharged from each of the buffer containers 62 need to be adjusted as a pressure of the gas in the tank and a pressure of the gas in the buffer 62 increase. Therefore, a control for filling of the gas into the tank by the gas-filling apparatus may be complicated.
Accordingly, the present invention is made in view of the above-mentioned conventional gas-filling apparatus, and it is mainly objected to avoid a complicated control for filling of gas into a pressure accumulator by a gas-filling apparatus.